I think you can't really consider an ethical problem in a vacuum. It's basically a matter of, ok, what is the basis for your ethics? What ethical framework do you think is best? And then it's a matter of deciding in that ethical framework, should abortion be allowed? It's a matter of, what is your ethical system? And then the conclusion about this and every other ethical problem follows logically, although in some cases the conclusion may be difficult to ascertain.
So, when we're discussing the morality of abortion, we're not really discussing abortion, we're discussing fundamental ethics (unless we all agree on an ethical framework and then discuss in particular what that framework logically leads to).
All the discussion is always "No, abortion is wrong" "Why?" "Cause God said so."
or, "Yes, abortion is permissible" "Why?" "Cause woman has a right to her body"
In each case they aren't really saying anything about abortion fundamentally, but they are just explaining that their beliefs imply a particular conclusion. Whether or not they're right rests exclusively on whether their foundations for ethics are right.
I'm rambling. My point is, if there is a correct answer to this problem (or any ethical problem), the only way to arrive at that answer is by knowing the correct overarching ethical worldview. Like, if Christianity is correct and the Roman Catholic Church is the correct interpretation of it, then abortion is wrong, regardless of any arguments to the contrary. If negative utilitarianism is correct, then there are many situations in which NOT having an abortion would be wrong (at the very extreme end they would argue that abortion is always right because nonexistence is preferable).
So if you wish to discuss abortion within a particular ethics, then I'd be happy to give my thoughts. If you want my personal opinion, I'm something of a hedonistic utilitarianist, and I think there are no strict rules, it needs to be judged on a case-by-case basis. I think for example, if a child is going to be born with something like Harlequin-type ichthyosis, it would be morally abhorrent not to abort it. On the other hand, I have a hard time seeing a fundamental moral difference between late-term abortion of a healthy baby and murder of a sleeping adult.